Various conventional systems exist for searching large volumes of electronic documents and displaying the results of those searches. For instance, keyword searches are a widely-used retrieval method for conducting general searches of electronic documents on the Internet. With keyword searches, a user typically retrieves a list of documents in response to entering one or more keywords into a search engine. The search engine runs a query against data collected during on-going crawls of web pages and returns documents containing the particular keyword(s) the user entered. Faceted searches allow users to search a set of documents by selecting various characteristics to serve as prerequisites. Moreover, conventional keyword and faceted searches often refine search results by allowing a user to manually select a document returned in the search results and then automatically constructing a new search query based on features (e.g., keywords) of the selected document to locate other documents similar to the selected document.
Internet keyword searches have limitations. First, web pages (i.e., documents), especially new or unpopular web pages, are infrequently re-crawled so information can be out of date. Second, web pages do not have a consistent format making content difficult to automatically discern. Third, web pages are organized based solely on the presence of a keyword in the document. Fourth, more precise keyword searches often require the construction of complex search queries using Boolean operators and field switches, which limits usability and makes it difficult for less technical users to find relevant search results. Individually and collectively, these limitations make keyword searches too restrictive. While a keyword search will generally return results (and, often, lots of results), there may be more relevant documents that are not returned by the query or appear far enough down the search results to be ignored by the user. In lay terms, you don't know what you don't know. It is with respect to these and other considerations that the present invention has been made.